FR2814435A1 - IMPROVED AXIAL RIGIDITY AND CASE-RESISTANCE PACKAGING ARTICLE - Google Patents

Abstract

The present application relates to a packaging article, in particular in the form of a bottle or a tube-bottle, comprising a wall (50) formed of at least one layer (51, 52, 53), formed at least in part a blend of a high flexural modulus polypropylene, and a low or very low density polyethylene.

Description

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The present invention relates to a packaging article, in particular in the form of a tube, a tube-flask, a can or a bottle, such as can be used for example, for the packaging of many household, food or cosmetic products.

Among the criteria that this type of packaging must meet is resistance to breakage in particular. Indeed, the material constituting such a packaging must be such that when it falls from the height at which it is generally found (that is to say typically from the hands of a consumer, or from a work surface) it does not not break.

In addition, the material must be such that the packaging has sufficient axial rigidity to withstand without crushing, the axial pressure necessary if necessary, for mounting, in particular by snapping, of a capsule or of a dispensing head. Such axial rigidity is also necessary when it is a question, during storage and transport, of stacking the packaging articles on pallets. Furthermore, the material must be such that the packaging article can be manufactured in using commonly used industrial manufacturing techniques, such as blow molding or coextrusion. To this end, in the context in particular of such a blowing extrusion process, the material must be able to weld, in particular in an area located at the bottom of the parison.

Finally, the cost price of such a packaging item must be as low as possible so as to be compatible with the economic imperatives of large distribution circuits.

It is known to produce bottles, in particular for the packaging of cosmetic products, in the form of a single-layer structure based on a polypropylene copolymer, the flexural modulus of which is typically of the order of 800 MPa . By way of example, mention may be made of the material sold under the brand BOREALISTM (reference CHC 307 MO), by the company BOREALISTM. Because of the relatively great flexibility of such a material, to give the packaging sufficient axial strength to which reference has been made above, it is necessary to have a wall of sufficiently large thickness. Typically such an average thickness is of the order of 800 μm. Obviously, the higher the cost of the packaging article, the greater the quantity of raw material required to manufacture it.

It is also known to produce such bottles based on polyethylene. By way of examples, mention may be made of the materials sold by the company DSM TM under the brand name STAMYLAN (references HD 7625 or HD 8621). The same problems arise with these materials as those mentioned with reference to the polypropylene copolymer. Typically, with this type of material, the thickness of the wall is of the order of 1 mm.

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 It is therefore one of the objects of the invention to produce a packaging article, in particular of the vial, tube or can type, and solving all or part of the problems discussed above with reference to conventional materials.

It is in particular an object of the invention to provide such a packaging article which is generally improved resistance to breakage and sufficiently axially rigid, in particular to resist stacking, or to allow the breakdown of a dispensing head or capsule.

It is another object of the invention to produce such a packaging article, at a cost which is as low as possible, and which can be manufactured using modern industrial techniques such as extrusion blow molding.

Still other objects will appear in the detailed description which follows.

According to the invention, these objects are achieved by producing a packaging article, in particular in the form of a bottle, a can or a vial, comprising a wall formed of at least one layer, constituted at least in part of a mixture of a polypropylene with high flexural modulus, and of a polyethylene of low or very low density. Advantageously, polypropylene is a homopolymer.

Indeed, surprisingly, the Applicant has discovered that the addition of low or very low density polyethylene to a polypropylene with a high flexural modulus, in particular to a polypropylene homopolymer, improves the resistance to breakage of the article. conditioning, infinitely more than it deteriorates the characteristic relating to its axial rigidity.

Therefore, compared to a bottle made only of polypropylene with a high flexural modulus, the packaging article obtained according to the invention has a significantly improved resistance to breakage, and an axial resistance which is not affected in any way. sensitive. Thus, for identical or even better performance, in terms of breakage resistance and axial resistance, the quantity of material required is lower than that required with conventional materials. The cost of the packaging article is therefore reduced accordingly.

In practice, polypropylene, because of its high flexural modulus and its high stability, provides the axial rigidity necessary for the packaging article. Low density or very low density polyethylene with which it is mixed improves the resistance to breakage of the packaging article, without significantly affecting its axial rigidity.

Within the meaning of the present invention, a high flexural modulus preferably means a flexural modulus greater than 1200 MPa, and preferably, greater than 1800 MPa, and more preferably, greater than 2000 MPa. Such a flexural modulus can be measured using the measurement the conditions of which appear in ISO standard 178.

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A titres d'exemple préférentiel, on utilise un homopolymère de polypropylène dont le module de flexion est de 2450 MPa, et commercialisé par la société TM MONTELL TM, sous la référence ADSTIF 680 ADXP. A titre d'exemple encore, on utilise un homopolymère de polypropylène commercialisé par la société DSMTM, sous la marque STAMYLANTM (référence P15 EK10). Le module de flexion de ce matériau particulier est de 2050 MPa.

As a preferred example, a polypropylene homopolymer is used whose flexural modulus is 2450 MPa, and sold by the company TM MONTELL TM, under the reference ADSTIF 680 ADXP. As another example, a polypropylene homopolymer sold by the company DSMTM, under the brand STAMYLANTM (reference P15 EK10) is used. The flexural modulus of this particular material is 2050 MPa.

As a further example, a polypropylene homopolymer sold by the company DSMTM, under the brand STAMYLAN (reference P12 E62) is used. The flexural modulus of this particular material is 1500 MPa.

polypropylène commercialisé par la société DSMTM, sous la marque STAMYLAN (référence P83 E10N). Le module de flexion de ce matériau particulier est de 1350 MPa. As an example again, although not preferred, a copolymer of

polypropylene marketed by the company DSMTM, under the brand STAMYLAN (reference P83 E10N). The flexural modulus of this particular material is 1350 MPa.

d'un agent nucléant, tel que le produit MILLIKEN commercialisé par la société du même nom. Preferably, the polypropylene has a degree of crystallinity greater than 40%, and preferably more than 50%, and more preferably still greater than 60%. The crystallinity of the polypropylene homopolymer can be increased by means

a nucleating agent, such as the MILLIKEN product sold by the company of the same name.

Low density polyethylene is understood to mean a polyethylene whose density is preferably between approximately 0.905 approximately 0.930. As an example of low density polyethylene, a material sold by the company EXXONTM under the trademark EXCEEDTM is used, the density of which is greater than 0.905.

Preferably, however, very low density polyethylene is used. A very low density polyethylene is understood to mean a polyethylene whose density is preferably less than about 0.905. Furthermore, the density of a very low density polyethylene is preferably greater than about 0.875.

Very advantageously, the packaging article according to the invention further comprises a second layer, internal to the first, and comprising at least in part, a low or very low density polyethylene. Preferably, the low or very low density polyethylene of the second layer is identical to that used in the composition of the first layer.

formée dans le fond de l'article de conditionnement, lorsque celui-ci est obtenu par coextrusion soufflage. En effet, lors de la fabrication d'un flacon par coextrusion, l'essentiel de la soudure est réalisé sur la couche interne du flacon. Les polyéthylènes, en particulier ceux obtenus par catalyse de type métallocène, ont une aptitude remarquable à former de telles soudures. This feature greatly improves the strength of the weld

formed in the bottom of the packaging article, when the latter is obtained by blowing coextrusion. Indeed, during the manufacture of a bottle by coextrusion, most of the welding is carried out on the internal layer of the bottle. Polyethylenes, in particular those obtained by metallocene type catalysis, have a remarkable ability to form such welds.

première couche, et le cas échéant, de la seconde couche, est obtenu par catalyse au moyen d'un catalyseur à haute sélectivité réactionnelle, en particulier, Preferably, the low or very low density polyethylene of the

first layer, and where appropriate of the second layer, is obtained by catalysis by means of a catalyst with high reaction selectivity, in particular,

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 metallocene type. A catalyst with high reaction selectivity means a catalyst having only one type of reaction site.

By way of example of very low density polyethylene obtained by metallocene catalysis, use is made of a material sold by the company DEX PLASTOMER under the commercial reference EXACT 0201, and whose density is approximately 0.902.

As another example, a material sold by the company DEX PLASTOMER under the commercial reference EXACT 8201 is used, the density of which is approximately 0.882.

Other materials, such as those marketed by DOS, under the trademarks ENGAGE or AFFINITYTM, may also be used.

Advantageously, the first layer contains 2 to 30%, and preferably 10 to 20% of low or very low density polyethylene. Too little polyethylene does not significantly improve the breakage resistance of the packaging article. Too much polyethylene too much affects the axial stiffness of the packaging article.

Where appropriate, in the second layer, the low or very low density polyethylene may be mixed with a polyolefin, in particular a polypropylene or a polyethylene. However, low or very low density polyethylene must be the majority in the blend. This feature allows, by adding a lower cost material, to reduce the cost of the packaging article accordingly.

Preferably, the thickness of the first layer represents 70 to 95%, and preferably, 80 to 95% of the total thickness of the wall. These intervals make it possible to guarantee a good compromise between the resistance to breakage of the packaging article and its axial rigidity.

couches. Cette troisième couche améliore encore la résistance à la casse de l'article de conditionnement, sans affecter de manière sensible le module de flexion de l'ensemble. Un telle couche pourra s'avérer nécessaire pour des articles de conditionnement de plus grande contenance, ou dont la forme les rend plus sensibles à la casse. In addition, the wall of the packaging article may comprise a third layer containing at least in part a low or very low density polyethylene, the first layer being disposed between the second and third

layers. This third layer further improves the resistance to breakage of the packaging article, without appreciably affecting the flexural modulus of the assembly. Such a layer may prove necessary for packaging articles of larger capacity, or whose shape makes them more sensitive to breakage.

et troisième couches. The material forming the third layer may be identical to that forming the second layer. This characteristic favors the coextrusion process, by authorizing a single supply source for the material forming the second

and third layers.

The total wall thickness can range from 450 µm to 800 µm, and preferably from 500 µm to 700 µm.

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 The packaging article according to the invention can be used for packaging a cosmetic product, in particular a hair product, personal hygiene product, skin care product or makeup product.

According to another aspect of the invention, a method of manufacturing a packaging article is also carried out, consisting in: a) by extrusion, making a parison with at least one layer formed at least in part of a mixture of a polypropylene with high flexural modulus, and a polyethylene of low or very low density; and b) blowing said parison into a mold comprising at least one cavity having a geometry corresponding to that of said packaging article.

Advantageously, the parison comprises at least two superposed layers, the second layer being disposed inside the parison, and comprising at least in part a low or very low density polyethylene.

Advantageously, step a) of the method consists in coextruding with the first and second layers, a third layer containing at least partly a low or very low density polyethylene, the first layer being disposed between the second and third layers.

The invention consists, apart from the arrangements set out above, of a certain number of other arrangements which will be explained below, with reference to nonlimiting exemplary embodiments, described with reference to the appended figures, among which: - Figure 1 shows an embodiment of a packaging article according to the invention; FIGS. 2A and 2B illustrate two examples of possible configurations of the wall of the packaging article shown in FIG. 1.

In FIG. 1, the packaging article 100 according to one embodiment of the invention, consists of a bottle 101. The bottle 101 comprises a body 102 delimited by a wall 50, and closed by a bottom 103. The body 102 has an elongated cross section and is formed by two large faces 104, 105, which can be elastically deformed under the effect of a pressure exerted perpendicularly to the long sides of the bottle.

de sortie 6. Sur sa face destinée à venir en regard de la paroi transversale 4, le couvercle 3 porte un picot 7 apte à s'engager de manière étanche dans le renfoncement 5 de manière à assurer une bonne étanchéité à la fermeture. Selon un premier mode de réalisation, la paroi 50 formant l'article de conditionnement 100 est d'une épaisseur d'environ 600 um, et est formée d'une seule couche, constituée d'un mélange comprenant : On the neck of the bottle is slammed a capsule 1. The capsule 1 comprises a body 2 on which is hinged a cover 3, via a hinge or articulation with spring effect 30. The body 2 of the capsule 1 has a transverse wall 4 in which a recess 5 is formed at the bottom of which an orifice is formed

outlet 6. On its face intended to come opposite the transverse wall 4, the cover 3 carries a pin 7 adapted to engage in a sealed manner in the recess 5 so as to ensure a good seal upon closing. According to a first embodiment, the wall 50 forming the packaging article 100 is of a thickness of approximately 600 μm, and is formed of a single layer, consisting of a mixture comprising:

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 a) 75% by weight of a polypropylene homopolymer whose flexural modulus is 2050 MPa, and sold by the company DSM under the brand STAMYLAN (reference P15 EK10); and b) 25% by weight of a very low density polyethylene obtained by metallocene catalysis. In this specific example, a material sold by the company DEX PLASTOMERSTM under the commercial reference EXAKT 0201 is used, the density of which is approximately 0.902.

"grand public"et pour lesquelles, sécurité du consommateur oblige, la barrière de la résistance à la casse est placée très haut. The container obtained has very good axial rigidity. Its overall resistance to breakage is improved significantly, compared to a container formed exclusively from the same polypropylene homopolymer with high flexural modulus. However, during the drop test, for a bottle whose geometry is close to that shown in FIG. 1A, and for a capacity of 200 ml, a certain fragility of the container is observed at the level of the bottom weld line, which fragility can make such a container unsuitable for certain uses, say

"general public" and for which, consumer safety requires, the barrier to breakage resistance is placed very high.

In the embodiment of Figure 2A, the wall 50 forming the packaging article 100 as shown in Figure 1 comprises two layers a layer 51, external to the container, and a layer 52, internal to the container.

The thickness of layer 51 is approximately 510 µm. The thickness of layer 52 is about 90 µm.

The material forming the layer 51 consists of a mixture formed at 85% by weight of a polypropylene homopolymer with very high flexural modulus (ADSTIF 680 ADXP), and at 15% by weight of a very low density polyethylene obtained by metallocene catalysis (EXACT "0201).

The material forming the layer 52 is the same very low density polyethylene as that used in the manufacture of the layer 51.

à la casse est vérifiée au moyen d'un test consistant à faire tomber l'article de conditionnement, rempli d'eau, d'une hauteur de chute de 140 cm. L'amélioration de ce paramètre peut être vérifiée en utilisant des hauteurs de chute plus importantes ou plus faibles, en fonction de la solidité que s'impose la société qui commercialise un tel article de conditionnement. The packaging article 100, obtained by blowing coextrusion of the two layers 51, 52, has both good resistance to breakage (including welds) and good axial rigidity. Improving resistance

for breakage is checked by means of a test consisting in dropping the packaging article, filled with water, from a falling height of 140 cm. The improvement of this parameter can be verified by using greater or lower heights of fall, depending on the solidity which the company which markets such a packaging article imposes on itself.

In the embodiment of FIG. 2B, the wall 50 forming the packaging article 100 as shown in FIG. 1 comprises three layers: a layer 53, external to the container, an intermediate layer 51, and a layer 52, internal to the container.

The thickness of layers 52 and 53 is about 60 µm. The thickness of layer 51 is approximately 480 µm.

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The material forming the layer 51 consists of a mixture formed at 80% by weight of a polypropylene homopolymer (STAMYLAN P15 EK10), and at 20% by weight of a very low density polyethylene obtained by metallocene catalysis (EXACTTM 8201).

The material forming the layers 52 and 53 is the same very low density polyethylene as that used in the manufacture of the layer 51.

The packaging article 100, obtained by blowing coextrusion of the three layers 51, 52, 53, has both good resistance to breakage (in particular at the welds) and good axial rigidity.

In the foregoing detailed description, reference has been made to preferred embodiments of the invention. It is obvious that variants can be made thereto without departing from the spirit of the invention as claimed below. .

Claims (14)

 1.-Packaging article (100), in particular in the form of a bottle, a canister or a tube bottle, comprising a wall (50) formed of at least one layer (51,52, 53) , consisting at least in part of a mixture of a polypropylene with high flexural modulus, and of a polyethylene of low or very low density.  2. Packaging article (100) according to claim 1 characterized in that the polypropylene with high flexural modulus is a homopolymer. 3. A packaging article according to claim 1 or 2 characterized in that it comprises at least a second layer (52), disposed inside the packaging article, and comprising at least in part, a polyethylene of low or very low density. 4.-packaging article (100) according to any one of claims 1 to 3 characterized in that the polypropylene has a flexural modulus greater than 1200 MPa, and preferably, greater than 1800 MPa, and more preferably, greater at 2000 MPa. 5.-packaging article (100) according to any one of claims 1 to 4 characterized in that the polypropylene at a crystallinity rate greater than 40%, and preferably, greater than 50%, and more preferably, greater at 60%. 6.- packaging article (100) according to any one of claims 1 to 5 characterized in that the density of the polyethylene of the first layer (51) and if necessary, of the second layer (52), is less than 0.930. 7.- packaging article (100) according to claim 6 characterized in that the density of the polyethylene of the first layer (51) and, if necessary, of the second layer (52), is less than 0.905, and preferably , greater than 0.875. 8-packaging article (100) according to any one of claims 1 to 7 characterized in that the low or very low density polyethylene of the first layer (51), and if necessary, of the second layer (52 ) is obtained by catalysis using a catalyst with high reaction selectivity, in particular of the metallocene type. 9. Packaging article (100) according to any one of Claims 1 to 8, characterized in that the first layer (51) contains 2 to 30%, and preferably 10 to 20% of low or very low polyethylene density.  10.- packaging article (100) according to claim 3 and all those which depend on it, characterized in that in the second layer (52), the low or very low density polyethylene is mixed with a polyolefin, in particular a polypropylene or polyethylene. <Desc / Clms Page number 9> 11. Packaging article (100) according to any one of the preceding claims, characterized in that the thickness of the first layer (51) represents 70 to 95%, and preferably 80 to 95% of the thickness. total of the wall (50).  12.-packaging article (100) according to claim 3 and all those which depend on it, characterized in that the wall (50) comprises a third layer (53) containing a low or very low density polyethylene, the first layer (51) being disposed between the second (52) and third (53) layers. 13.-packaging article (100) according to claim 12 characterized in

 that the material forming the third layer (53) is identical to that forming the second layer (52). 14.-packaging article (100) according to any one of the preceding claims, characterized in that the total thickness of the wall (50) ranges from 450 µm to 800 µm, and preferably from 500 µm to 700 µm 15- Use of a packaging article (100) according to any one of the preceding claims for the packaging of a cosmetic product, in particular a hair product, personal hygiene, skin care, or makeup. 16-A method of manufacturing a packaging article (100) according to any one of the preceding claims characterized in that it consists in: a) by extrusion, making a parison with at least one layer (51, 52, 53), formed at least in part from a mixture of a polypropylene with a high flexural modulus, and of a polyethylene of low or very low density; and b) blowing said parison into a mold having at least one imprint whose geometry corresponds to that of said packaging article.  17. -A method according to claim 16 characterized in that step a) consists in coextruding with the first layer (51), a second layer (52), disposed inside the parison, and comprising at least in part , a low or very low density polyethylene.  18. -A method according to claim 17 characterized in that step a) consists of coextruding with the first and second layers (51, 52), a third layer (53) containing at least partly a low polyethylene, or very low density, the first layer (51) being disposed between the second (52) and third (53) layers.